Harmonic signaling for polystation telephone-lines.



PATENTED FBB.12, 1907. v

w" w. DEAN. HARMONIC SIGNALING FOR POLYSTATION TELEPHONE TLINES.

APPLICATION FILED AUG. 8. 1906.

QR" muse: 1

UNITED srAT s PATENT OEEIOE- WILLIAM W. DEAN, OF ELYRIA, OHIO, ASSIGNOR r0 THE DEAN ELECTRIC COMPANY, OF ELYRIA, OHIO, A CORPORATION OF OHIO.

HA'RI'VIONIC SIGNALING Fon' POLY TATION TELEPHONE-LINES. I

Specification of Letters Patent. Application filed August8,1906. Serial No. 329.750.

Patented Feb. 12,1907.

To aZZ whom it may concern:

Be it known that I, WILLIAM W. DEAN, a citizen of the United States, residing at Elyria, in the. county ,of Lorain and State of ()hio, have invented certain newand useful Im rovements 1n Harmonic Signaling for P0 ystation Telephone-Lines, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention relates to harmonic signal-.

ing for polystation telephone-lines, and comprises 'a method of operation which maybe. practiced with the apparatus and circuits illustrated in my Patent No. 827,087, dated July31, 1906.

According to methods heretofore em-l but form parts of one machine, whose speed is rendered fairly constant by means of overning devices which it is unnecessary ere to describe. According to some systems -the ringer-armatures at the substation,

which constitute reeds, are tuned so as to be in exact accord with the several different ringing-currents by which they are to be respectively actuated. According to other systems the ringers are overtuned or undertuned, according to their design and the exigencies of the case; but my present invention is not limited to any of these in particular, but is, in fact, applicable to all of them, since its aim is to correct a defect found in th emall.

to its own tuned'bell, by winding generators so that their respective outputs shallbe of diverse voltages. I find it very effectlve to ta e and ahighdrequncy generator of high v0 tage. It is evident that by this method the high-frequency bells, which are always hardest to ring, can betuned and adjusted sible without being afi'ected by th'e'low-fre increase the margin of selection, I also find it expedient to make the condensers of low-frequency bells of lar er capacity than the others, those for the h being, in fact, of very small capacity.

My invention is illustrated in the accompanying drawing, which is a diagram of a ratus throu h and by which any station on the line can e selected andrun'gf In the drawing, A, A, A, and A are subscribers stationsall connected to the same pair of line-wires. 1 2. At each subscribers station I provide the usual transmitter T, receiver R, switch-hook H," and whatever to the ringer Q and the condenser C. I have station A only, their inclusion at each of the other stations being und ertsood At the central office the line-wires tenninate, respectively, in the springs j'y" of-the jack J, which may be a single line-jack of a simple or transverse board or may be taken as the type of multiple jacks on a multiple switchboard. In the latter case a testthimble would be required for each jack, and 'I have illustrated it for that reason. The line-signal L is shown as a (lIOP-aDIIUD- ciator connected to theline through cut-off contacts in the jack, its circuit 19 20 including asource of signaling-current B.

Cooperating with the jack and intended to erss line and other lines or circuits is the plugP, which is here supposed to be the calling-plug of a pair Whose corresponding contacts are connected together through cord conductors 3 to 11 and 4 to 12. I have shown theplugl? with a tip-contact 1) connectedto the conductor, 3 and the sleevecontact connected to the conductor 4. The con uctors 1 1 and 12 are therefore supposed to be similarly connected to the tip make a low-frequency generator of low v0l-.

more delicately than otherwise wouldbe pos- .polystation line and the central-ofiicerappa- 0ther apparatus may be required in addition shown the telephone set and switch-hook at quency currents. In order to still further ighest frequency bells establish connection between the subscribthe calling apparatus and sleeve ofthe twin or answering plug of the pair. As my invention relates/only to and circuitml have not illustrated the answering end as the plug-cord, its arran ement being familiar to all those skilled in t cart.

I In'the callin end of the cord fhieh'i have-illustrate I I{provide four selective g gT ys: 1. 1

when actuated to connect to the cord and thence Ito, the. line onev of t four ringing' generators G, G;, f-G", and .and thereby throw out current of the proper character to ring the bell at any particular one, of the four stations AA A A Each of theseringingkeys-has a'pairof springs with front and back) contacts; Those of the key K are marked 7c and kc, and in their normal condition of disuse they rest upon their front contacts connected to the conductors 5 and.

6, which pass thence to the springs 1c and k of the key K", these in turn normally resting ried from the terminals of wires5 and 6 and close a circuit forgenerator G, which may be connected springs k and k the normal resting contacts of these springs being connectedto The plug 11 on front contacts connected through W1res 7 and 8 to the s rings k and k of the key K which normally rests upon contacts through wires 9 and 10 to the the conductors 11 and 12. Each of the keys is provided with an actuating button or lever with a cam, whichupon' actuation of the button of lever acts to spread apart the s rings,

breaking the connection between con uctors 3 4 and 11' 12 and establishing a connection from the conductors 3 4 to one of the generators. Thus uponactuating the button or lever'of key K the springs k and k0 are car traced as follows: on the one side from the tip p throughj conductor 3 to the spring is, thence to the generator G, and by wires 17 and 18 to the ground at g; on the other side fromthe sleeve 1) through conductor 4 to'the" springico; and thence ect to the ground; having been inserted in the jack J when the key Kis thus actuated, current fromthe generator G will pass out from, the

. line-;wire's, 1 2 to actuate the-bell at the cortions A responding station.

The ringers Q, Q, Q, and Q at the sta' A A A, respectively, are designed to respond to and be actuated by currents of the following frequencies: for ringer Q, current at 66.6.cycles; for ringer Q, current at fifty cycles; for ringer Q current at 33.3

cycles, and for ringer Q current atf16.;6.

cycles dper: second. The generatorsG, G, G an are wound and run so as to produce currents of the four frequencies mentioned. that is, generator Ggives current at 66.6 cycles, G currentat fifty cycles, Gr cur- I rent at 33.3 cycles, and G current at 16.6

cycles. There is nothing essentially novel in the and K each adapted system thus far described. With some slight modifications it might be taken as a type of that class of systems familiar to telephone engineers under the name of harmonic selective systems. My present in- .vention, however, may now be understood.

and will be described as applied to-the fore going. It consists, essentially, in giving the" generators G, G, G ties of speed or winding, or both, thatthe and G3 such peculiariwill produce their res ective currents, at d1? verse-voltages, as wel as of diverse frequen cies. Thus the generator G, Idesigntoproe generator G at one hundred and fifty,sgenerator G at one hundred, and generator G? at fifty. In other words, I make the, highduce current at a voltage of two hundred,

frequency generatorsalso high-voltage lnachines, relatively speaking, and the low.fr c* uency generators I make low-voltage'mac ines. Oorrespondingly I may'wind the ringers Q Q Q Q of whatever resistance, or,

make the condensers in the ringer branches of diverse capacities. The ringer Q at statron A be ng tuned to respond to current at a frequency of 66.6 cycles per second, which is the maximum employed in the system, I include in this ringer branch the minimum capacity of one-fourth microfarad. The ringer Q being tuned to respond to cur rent at fifty cycles, I double the capacity,

Q 1- again double the capacity, making it'one microfarad, and for ringer Q I provlde, twonncrofarads. The condensers C, 0, C and as I have shown in the drawing, I preferably making it onehalf microfarad. For ringer Ioo C have progressively increasing capacities, therefore, the largest capacity, C corresponding to the lowest fre uency and the lowest-voltage current, whic is thrownout byth e generator G scription that there will belittle or no chance for leakage, and consequently interference, by low-frequency current through the highfreiiuency branches at stations A A The hig for mechanical as well as electrical reasons,

[and since I have cut down the capacity to a small fraction and the voltage or pressure of the current also to a small fraction of the it to bedistinctly understood that all appli- I It will be apparent from the foregoingdefrequency hells are the hardest to ring maximum, t-he frequency being alreadya:

adapted to respond-to a given frequency,

' operate said devices, and suitab y limiting which consists in tuning the signal-receiving supplying currents of suitable frequencies tocations of this broad idea, whatever be their specific form, and all the modifications which maybe made therein are contemplated by me as Within the scope and purview of my invention.

' Havingthus described my lnvention, what I claim, and desire to secure by Letters Pat-' cut, is

1. The method of harmonic signaling mitted at each frequency. 4

3. The method of harmonic selective signaling which'consists in arranging tuned signal-receiving devices in parallel branches of the signaling circuit, each device being supplying currents of suitable fre uencies to the amount of current effectively supplied to each signal-receivin device.

4. The method 0 harmonic selective signaling which consists in arranging tuned signal-receiving devices in parallel branches of the signaling-circuit, each device being responsive to a given frequency of current,

operate any of said devices at will, and regulating voltages so that they will be approximately proportional to the frequencies and the currents su plied.

5. The met 0d of harmonic signaling which consists in tuning signal-receiving devices so that each will respond to a given frequency, connecting the said devices in parallel branches of a signaling-circuit, and pre,-' venting interference by fixing the voltage of the signaling-current at each fre uency so that the amount of current whic will be efiectively transmitted through 'each signal" .device. will be inversely proportional to the; frequency for which that device is tuned, and the amount of current at low frequencies which can be transmitted through the-dice vices tuned for high frequencies will be 1135 sufiicient to operate the same.

6. The method of harmonic selective si-g naling over parallel circuits-without interferen'ce which" consists in regulating the vol-- tages'of the several signaling-currentsisoas to be proportional tothe frequencies,

' 7. The methodof'harmomc signaling over.

parallel branches without interferencewhich consists in-tuning the si al device in each branch to respond to a given fre uency,;adjusting the capacities of the branc es so as to be approximately inversely proportional to the frequencies, and finally adjusting the voltages of the signaling-currents so as to be approximately directly proportional to the frequencies emploiyed.

In testimony w ereof I- aflix my signaturein presence of two witnesses.

WILLIAM Witnesses:

RAY H. MANSON, N; SMALLWOOD. 

